[7/21] Radiative and mechanical feedback into the molecular gas in the LMC: N159W as a test-bed

Abstract

  The interaction between stars and their surrounding interstellar medium (ISM) is of critical importance for the evolution of galaxies. In this talk, I will present our investigation of the physical properties and excitation mechanisms of the warm molecular gas in the Large Magellanic Cloud (LMC). As a pilot study, we focused on N159W, one of the most active star-forming regions in the LMC, and observed the target with the Herschel SPIRE FTS, detecting CO rotational transitions up to CO(12-11). Our radiative transfer analysis on 10 pc scales revealed the presence of very warm (400 K) and moderately dense (1000 cm-3) molecular gas in the LMC for the first time. In combination with other gas and dust tracers, we examined the observed CO line ratios using state-of-the-art models of photodissociation region (PDR) and shock, finding that mechanical heating by low-velocity shocks, rather than ionizing sources (UV photons, X-rays, and cosmic-rays), is the dominant heating source for CO. Finally, I will finish the talk by presenting future work, which includes our ongoing investigation of the starbursting 30Doradus region.